Q.I’m confused about the use of oats in the gluten-free diet. I thought oats were not safe but now I hear they are allowed. What’s the truth?

Shelley Case: In a sense, you’re right on both counts. Historically, oats were not allowed on the gluten-free diet (GF diet) used to treat those with celiac disease. Oats were believed to trigger the same toxic reaction in the small intestine as wheat, rye and barley. However, many studies from the United States and Europe reveal that consumption of oats is safe for the majority of children and adults with celiac disease.

Most of these studies used pure, uncontaminated oats, but it should be noted that a very small number of individuals with celiac disease may not even tolerate pure oats. The mechanism causing this intolerance has yet to be established.

Based on this new research, a growing number of health professionals and celiac organizations around the world now allow consumption of moderate amounts of pure, uncontaminated oat products in a GF diet. In Canada, Health Canada has issued a position paper[2] on the safety of oats in celiac disease, while the Canadian Celiac Association’s professional advisory board has developed a position statement[3] on using pure, uncontaminated oats. It says that adults with celiac can safely consume half to three-quarters of a cup (50 to 70 grams) of dry rolled oats per day. For children, it’s one-quarter cup (20 to 25 grams) per day.

Unfortunately though, most commercial oat products on the market have been cross-contaminated with wheat, barley and/or rye, which occur during harvesting, transportation, storage, milling, processing and packaging.

The good news is there are specialty companies in North America and Europe who produce pure, uncontaminated oat products that are grown on dedicated fields and equipment and packaged in dedicated gluten-free facilities. The American companies include Bob’s Red Mill, GF Harvest (formerly Gluten-Free Oats), Montana’s Gifts of Nature and Montana Monster Munchies (Legacy Valley). The Canadian companies are Cream Hill Estates (Lara’s brand) and Avena Foods (Only Oats brand).

Many other companies are using these pure, uncontaminated oats from the producers listed above (and in the chart below) in their gluten-free products. Examples include Glutenfreeda Foods’ oatmeal, NoNuttin granola bars and granola, and Holly’s oatmeal.

Before adding pure, uncontaminated oat products to your diet, I recommend that you consult with your physician and dietitian. It is also very important that your celiac disease be well-controlled on the GF diet and that you have no gastrointestinal complaints.

A diet containing oats is often higher in fiber than the typical GF diet, therefore some individuals may experience a change in stool pattern or mild gastrointestinal symptoms such as abdominal bloating and gas. This will resolve as the body adjusts to the change in the amount and type of fiber.

When adding a new fiber source such as oats, it is important to consume more fluids, especially water.

Shelley Case is a consulting dietitian and author ofGluten-Free Diet[13]: A Comprehensive Resource Guide. She is on the advisory boards of the Canadian Celiac Association, the Celiac Disease Foundation and Gluten Intolerance Group.